DE202016102826U1 - A heat shrinking device for packaging with heat-shrinkable film equipped with sectioned burners - Google Patents

Abstract

A heat-shrinkable device for packaging with heat-shrinkable film on charges advancing along a transport line (1c) along a longitudinal axis (XX) comprising a support bridge (1) arranged astride the transport line on which a ring-shaped furnace is vertically displaceable mounted, which is provided with a plurality of gas burners, each gas burner consists of a box-shaped body with outlet nozzles, which are suitable for expelling warm air from an outdoor area to a central working area of the annular furnace, in which a charge to be packaged is to be placed the burners comprise a first pair of transverse burners (2,3) arranged in opposite directions, and a second pair of lateral burners (4, 5) arranged opposite and substantially perpendicular to the first ones, at least one of the transverse burners (3) horizontally displaceable along an approach / distance axis in the Hinblic k is arranged on the other of the transverse burner (2), characterized in that at least the lateral burners (4, 5) in the length in at least two energy-independent sections (4a, 4b; 5a, 5b) are subdivided to form respective warm air streams which can be regulated independently.

Description

Field of the invention

The present utility model relates to a heat shrink device for packaging with heat-shrinkable plastic film. More specifically, the pattern relates to an annular furnace structure with gas burners intended to surround a charge to be packaged.

State of the art

As is known, heat-shrinkable plastic film is used in the packaging sector, which is applied in a cold state to the material to be packaged in a loose state - both in the form of a wrap and in the form of a hood - and then brought by heat to the charge to the charge ,

The means by which heat shrinkage of the plastic film on the charge is carried out are generally referred to as heat shrink furnaces. These typically consist of a plurality of heating elements disposed annularly around the charge and adapted to produce warm blast air (at a temperature of up to about 300 ° C) that is driven to flow around the plastic wrap surrounding the charge so that they can flow Heat shrinkage according to the commonly known modalities causes.

The heating elements can be of two types, electrically or gas operated.

The electrical heating elements have a lower power, but are very easy to regulate. Therefore, it is a common practice to place several small heating elements around a heat shrink area (in which the charge to be packaged is placed), which are mounted so that they can be individually approached and removed from the load and, in any case, individually temperature controlled , In this way, the heat-shrinkable film can be heated in a very precise and efficient manner. An example of this technology is through DE3826358 or EP595.108 shown. However, this type of heating element requires a total of high consumption of electrical energy, which is not desirable in many contexts.

The gas heating elements - which are the subject of the present application - are much more widespread because they have a higher unit performance and are therefore more suitable for mass production. The problem that arises with this type of heating burner concerns its ability to regulate, which ultimately has an impact on operating costs.

In most cases, for reasons of structural comfort and handling, the heat-shrink oven provides an annular box structure (typically quadrangular) on which are mounted multiple gas burners and outlet nozzles directed into the interior of the annular periphery in which to package Cargo is stored. The annular structure is typically mounted in a vertically movable manner on a support bridge which is placed astride an advancing path for the charges to be packaged.

Such an annular structure has dimensions such that it can surround the charge and maintain the outlet nozzles at the correct distance from the lateral surfaces of the charge so as to effect heat shrinkage of the film without burning it. When the ring is moved in the vertical direction, the heat given off by the burners dissipates on the entire foil, which disguises the charge in height.

Over time, work experience has shown that shrinkage of the film is optimal when the outlet of the burners is maintained at a distance of between 20 cm and 30 cm from the film. However, as can easily be appreciated, the prior art annular structure briefly described above is substantially rigid and therefore can guarantee the optimum distance from the charge only in specific cases, that is, when the cross section of the cargo is in plan with a certain reduction factor corresponds to the project section of the furnace.

On the other hand, if it is necessary to use the same equipment for charges of very different dimensions, the heat is very often transferred to the charge in a non-ideal way. Under these conditions, the gas burner is often inefficient, and consequently, in order to maintain the correct supply of heat to the packaging film, it may be essential to increase the warm airflow and / or prolong the times when exposed to the warm airflow associated with a considerable increase in time and energy.

Institutions tackling this problem are in the Italian utility model no. 272.811 and in Italian Patent No. 1,400,702 described, both in the name of the same Applicant, which is hereby incorporated by reference for the purpose of better understanding of the present invention.

Both solutions already presented are satisfactory, but it has been found that there is a framework for improvement. in the Specifically, there is a need to provide a device that does not require large shifts in load and reduces execution times, although a substantial economics of processing (especially energy) and adaptability to the dimensions of the cargo, at least within the most common Dimensions (Euro pallets) is maintained.

Complex measures have already been proposed for respectively changing the housing structure for distribution or for moving the outlet nozzles of the burners, so that the release of the heat is adjusted to the dimensions of the load to be packaged, but this entails structural and operational expenses often not rewarding. Known solutions of this kind are for example in EP 244622 . DE 4318753 and DE 2852967 described.

Summary description

The object of the present invention is therefore to propose a device for heat shrinking with gas burners which is capable of - in an extremely simple and rapid manner and every time a change in the type and dimensions of the load proves necessary - the modalities the heat output on the heat-shrinkable plastic packaging, whatever the shape and dimensions of the cargo to be packaged, adapt, with the dead times reduced to a minimum and the energy consumption is maintained in proportion to the dimensions of the charge.

The object is achieved with a heat shrinkable packaging for heat shrinkable film packaging having the features set forth in claim 1; the secondary claims relate to some particularly preferred aspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In any event, further features and advantages of the exemplary device will become more apparent from the following detailed description of a preferred embodiment thereof, given by way of example and illustrated in the accompanying drawings, in which:

1 is a schematic plan view of a pattern-like device in the phase of processing a charge with large dimensions in plan view;

2 a schematic plan view of the same device as in 1 is in the stage of processing a charge of small dimensions; and

3 a view of the same device in frontal elevation is.

DETAILED DESCRIPTION OF A FORM AS AN EXAMPLE

As shown schematically in the figures, a heat shrinking device comprises a rigid support bridge in a manner known per se 1 , fixed and with a pair of uprights 1a . 1b which straddles a transport road 1c (for example, a runway) for moving a charge C is set. This bridge 1 is adapted to hold and move the gas burner devices that produce the required warm air to perform the heat-generated shrink-wrapping operation of the film of plastic packaging material in the following more clearly explained manner.

On the support bridge 1 is a quadrangular rigid frame 1d suspended, whose height position is regulated by a vertical drive system, for example holding chains 1e , which depend on an engine M

On the rigid frame 1d are mounted several box-shaped elements, the burner devices 2 . 3 . 4 and 5 which are suitable to allow flows of warm air to the center of the frame 1d to generate where a charge to be packaged should be stored. The burner devices are equipped with means known per se for generating heat, blowing-air regulation of the direction and the temperature of the warm air flow. These devices will be referred to simply as "burners" hereinafter, and no further details will be given as they are knowledgeable technicians and do not form per se the subject of the present invention.

Because the burner 2 - 5 on the vertically movable frame 1d attached, it is possible to distribute the warm air along the entire height of the charge C.

Also in a known manner are on the annular frame 1d the burners at least in two transverse burners 2 . 3 divided, that is arranged perpendicular to the longitudinal axis XX of the movement of the charges, and in two lateral burners 4 . 5 , that is parallel to the longitudinal axis XX. These burners are shown very schematically in the drawings as box-shaped elements which are drawn very much in length, whose slot is intended for the distribution of the warm air (not visible) parallel to the longitudinal side of the latter and with the flow of hot air towards the charge Must be in the middle of the frame 1d is stored.

In addition, at least one of the transverse burner - in the case shown, the burner 3 - on the support frame 1d mounted horizontally movable along the longitudinal axis XX of the plant, that is, in approaching and away from the opposite burner 2 , As an alternative, both are cross burners 2 and 3 along a corresponding axis XX horizontally to each other movable. In this way, the relative distance between two opposite transverse burners 2 and 3 be adjusted as desired by adjusting it to the appropriate dimension of the cargo to be packaged.

This movement allows, from the in 1 shown arrangement, which is suitable for a charge C of maximum dimension, to the arrangement in 2 to go, which is suitable for a charge Ci with a much smaller length dimension.

Consequently, the other pair of side burners 4 and 5 an overall extent suitable for supplying heat to the entire length of a charge C corresponding to the maximum distance between two transverse burners (that is, the one in 1 shown charge).

According to the pattern, the two side burners 4 and 5 lengthwise into two or more operative sections 4a . 4b respectively 5a . 5b divided or divided. In particular, the operative sections are arranged lengthwise one after the other on each side and are energetically autonomous, that is, they can be independently activated / deactivated for the production of warm air and consume an amount of energy proportional to their own dimension in the air Comparison to the overall dimension of the two side burners 4 and 5 is.

Every section 4a - 5b can therefore be activated / deactivated according to the requirements, so that two respective more or less extensive flows of warm air are formed, depending on how many of them are activated. As shown, each section has 4a - 5b its own fan 6 to stabilize the warm airflow (although this is not absolutely necessary if a single fan and several throttle valves are provided on the different burner sections).

In particular, it is with a simple separation in the box-shaped lateral bodies of the burner 4 and 5 it is possible to fundamentally adapt the burner ring to two typical charge dimensions, referring to two pallets of standard dimensions.

The device thus described has a relatively simple and intuitive way of working.

In the in 1 In the state shown, the charge C awaiting a heat-shrinking operation is a maximum dimension charge, that is, it occupies all the available space within the annular frame 1d one.

In this state, the cross burners 2 and 3 and all sections of the side burner 4 and 5 active.

In the in 2 In the illustrated state, the charge Ci waiting for a heat-shrinking operation is a charge of reduced length dimension; therefore it extends over about half of the maximum between the two transverse burners 2 and 3 available longitudinal space.

In this case, the charge Ci is at the correct distance in the vicinity of the first transverse burner 2 positioned, and the other cross burner 3 shifts to the first burner 2 and in turn brings him to the correct distance to the charge Ci.

In this way, the entire extent of the lateral burners 4 and 5 that is outside of the two transverse burners 2 and 3 limited circumferential line, not used to supply heat to the charge. It is therefore possible the sections 4b and 5b which are outside the two transverse burners, which is an obvious advantage in terms of energy consumption.

According to a preferred feature of the pattern, the two sections have front and rear each side burner 4 . 5 different lengths, as shown schematically in 1 and 2 shown. This arrangement has the advantage that - if also the second transverse burner 2 and not just the first cross burner 3 horizontally movable in the direction of the second burner 2 attached - the charge Ci in a more or less advanced position with respect to the rigid frame 1d can be arranged, depending on whether it has length dimensions, those of the front sections 4a . 5a or those of the back sections 4b . 5b similar ones that were previously treated. In essence, power consumption is better adaptable to the dimensions of the load.

On a theoretical level, each side burner can be divided into a number of sections, but in fact the solution described is that which represents the best compromise between energy advantages compared to higher ones Design and maintenance expenses could be achieved, which would imply the addition of additional sections.

According to a variant of the model are also the side burners 4 and 5 horizontally slidably mounted along an axis perpendicular to the longitudinal axis XX axis in relative approach or distance from each other.

In this case, it becomes possible with respect to a charge having, for example, substantially the same length dimensions as the charge C of FIG 1 but has a smaller transverse dimension (charge C3 with dashed lines in 1 shown) -, the side burner 4a . 4b respectively 5a . 5b to approach the side walls of the charge C3. Advantageously, the various sections that make up the side burners 4 and 5 assembled, independently slidably mounted. This allows greater flexibility in matching the torch ring to the dimensions of the charge presented to the heat shrinker without interference between the cross burners and the side burners.

In the case of this variant, it is possible to treat in the best possible way also smaller charges having, for example, a transverse dimension like that of the charge C3 and a length dimension like that of the charge Ci or C2. If, for the sake of better understanding, the charge Ci in 2 Reference may be made to the first transverse burner 3 on the in 2 shown manner and at the same time only the two front sections 4a . 5a the lateral burners are approximated laterally to the charge, without any possible interference of the rear sections 4b . 5b with the first burner 3 to be afraid is because of these sections 4b . 5b remain immobile. Since the dimensions of the charge C along the transport road can be automatically detected, a control unit can also provide for the mutual distance of the burners before the activation of the heat shrinking furnace 2 . 3 . 4a . 4b . 5a and 5b in the longitudinal and / or transverse direction, so that between the different sections of the burners and the sides of the charge C always the best possible distance and the lowest possible energy consumption can be determined.

Thus, if it were to be charges of frequent dimensional changes, it is advantageous to provide sensing means in advance of the device or in firm connection with the torches so that a signal is sent to a control controller for correct regulation of the distances.

Conversely, if it is intended to handle fairly large cargo bins of the same dimensions, it is possible to carry out the above-mentioned regulations in manual mode.

With the device according to the pattern, the goal is achieved in this way, that is to say, a heat-shrinking device for the packaging of charges capable of providing excellent quality of the heat-shrunk packaging at a low energy cost, thanks to the fact in that it adapts easily to the ground plan dimensions of the load and therefore keeps the burners at an ideal distance from the charge. This adjustment is made by a simple subdivision of the box-shaped body of the burner, and this also at very low cost.

It should be understood, however, that the protection of the above described pattern is not to be construed as limited to the particular example embodiment shown, but extends to any other design variation that falls within the scope of the following claims.

It is understood, for example, that the rectangular dimension shown in the figures could also be rotated by 90 °, that is, it is provided that the longer side of the ring of the heat-shrinking furnace is arranged transversely to the direction of movement X-X of the charges.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3826358 [0005]
• EP 595108 [0005]
• IT 272811 [0011]
• IT 1400702 [0011]
• EP 244622 [0013]
• DE 4318753 [0013]
• DE 2852967 [0013]

Claims (4)

Heat-shrinkable device for packaging with heat-shrinkable film on charges along a transport line ( 1c ) according to a longitudinal axis (XX), which is a support bridge ( 1 ) mounted astride the transport line on which is vertically slidably mounted an annular furnace provided with a plurality of gas burners, each gas burner consisting of a box-shaped body with outlet nozzles adapted to receive warm air from an exterior area ejecting a central working area of the annular furnace in which a charge to be packaged is to be deposited, the burners comprising a first pair of transverse burners ( 2 . 3 ), which are arranged oppositely, and a second pair of lateral burners ( 4 . 5 ), which are arranged opposite and substantially perpendicular to the first, wherein at least one of the transverse burners ( 3 ) horizontally displaceable along an approach / distance axis with respect to the other of the transverse burners ( 2 ), characterized in that at least the lateral burners ( 4 . 5 ) in length in at least two energy-independent sections ( 4a . 4b ; 5a . 5b ) are subdivided to form respective warm air streams which can be regulated independently. A heat shrinking device for packaging as in claim 1, characterized in that the sections of each pair ( 4a . 4b ; 5a . 5b ) side burner ( 4 . 5 ) have different expansions, so that they generate warm air flows with different expansion in the floor plan. Heat-shrinking device as in claim 1 or 2, characterized in that the one and / or other of the transverse burners ( 2 . 3 ) are mounted horizontally displaceable along the axis of mutual approach / removal. Heat-shrinkable device as in claim 2 or 3, characterized in that the lateral burners ( 4 . 5 ) are in turn mounted horizontally displaceable along an axis of mutual approach / removal.

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